Wireless communication systems, such as the 2nd Generation (2G) (otherwise referred to as Global System for Mobile (GSM) communications) and the 3rd Generation (3G) of mobile telephone standards and technology, are well known. An example of such 3G standards and technology is the Universal Mobile Telecommunications System (UMTS), developed by the 3rd Generation Partnership Project (3GPP) (www.3gpp.org).
Typically, wireless communication units, or User Equipment (UE) as they are often referred to in 3G parlance, communicate with a Core Network (CN) of the 3G wireless communication system via a Radio Network Subsystem (RNS). A wireless communication system typically comprises a plurality of radio network subsystems, each radio network subsystem comprising one or more communication cells to which UEs may attach, and thereby connect to the network.
The consumer pressure for less expensive and faster services anytime and to any location, has led to the requirement for significant improvements in the planning and optimization of such cellular communication networks, in order to make the most of limited resources.
A problem with current planning and optimization techniques, as identified by the inventors of the present invention is that the same parameters for estimating path loss are typically used throughout all sectors of a geographical area of interest, such as a city, country, etc. However, in reality, path loss characteristics vary from sector to sector. As a result, such known planning and optimization techniques result in inaccurate and unrealistic pathloss estimations, and thus sub-optimal planning and optimization of the network.
In order to provide more accurate pathloss estimations for network planning and optimization, the pathloss characteristics for individual sectors are required to be more accurately modelled. However, traditionally in order to achieve this, drive test data is required to enable the pathloss characteristics for individual sectors to be accurately calibrated. Drive tests are typically carried out in regular intervals to provide a measure of the quality of the network, or may be specifically performed to investigate certain problems, such as when the performance of the network is not operating as well as desired. In such drive tests, a vehicle records data such as cell scrambling codes and their corresponding received signal strength, along with location information, for example obtained via a GPS (Global Positioning System) receiver. Performing such drive tests throughout an entire network is an expensive and time consuming undertaking. Furthermore, such drive test data is required to be continually updated in order to take into account environmental changes, such as the construction of new buildings, growth of trees and changes in their foliage, etc.
Thus, there is a need for an improved method and apparatus for deriving pathloss information within a cellular communication network, whereby at least some of the above mentioned problems with known techniques are substantially alleviated.